The B727 was one of those "built like a tank" machines. They were old school but fun to work on. They had the old JT8D-15 engines that sounded like a fighter jet when they took off. I loved to watch them rotate on a wet runway as the #2 engine shot up a rooster tail. Toward the end of their life cycle we had to install hush kits on all of the planes because they were so loud that they were banned in most major cities. Here's a pic of a hush kitted -15 where you can notice the large extension on the exhaust duct.
The Cooper vane was added after the famous DB cooper escape in which the air stairs were opened in flight. The vane was a simple yet effective means to essentially block the door with a wedge so it couldn't be opened at high speed.
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